A presenter for a London-based radio service critical of the government of Malaysia's Sarawak state who was reported missing has said he is safe but in hiding over fears for his safety.

Radio Free Sarawak presenter Peter John Jaban was taken away by three men shortly after arriving on Thursday in Sarawak on the huge island of Borneo.

Jaban's colleagues and state opposition politicians had said they were worried authorities had detained Jaban, who has filed reports critical of the state government.

But Jaban said in a posting seen Monday on Sarawak Report, a related website, he knew the three men -- "good Samaritans who helped me get away" -- and had gone with them over fears that authorities would detain and abuse him.

"I am fearful of what they (police) will do in custody, when you are in their hands," Jaban was quoted as saying.

"I am sorry I left so abruptly," he said, adding he was prepared to meet police, provided they guaranteed his safety.

Radio Free Sarawak broadcasts for two hours daily in reports targeted at Sarawak's large tribal communities.

The reports typically focus on alleged graft by the state government in the harvesting of the state's rich rainforest timber resources.

The service was founded by Clare Rewcastle Brown, the sister-in-law of former British prime minister Gordon Brown.